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Question 5 1.5 points Save Answer An organism identified as Staphylococcus was challenged by several antibiotics using the Kirby-Bauer protocol. EACH of the following drugs showed a zone of inhibition of 19 mm. Given these results, which antibiotic would be most useful in treatment against this organism? (Use the information on the reference chart below.) Drug Resistant Intermediate Susceptible Ampicillin < 28 mm 28 mm > 28 mm Erythromycin < 13 mm 13-22 mm > 22 mm Penicillin G 28 mm 28 mm > 28 mm Streptomycin < 11 mm 11-14 mm > 14 mm Streptomycin Erythromycin Ampicillin ооо Penicillin G A Moving to another question will save this response. << < Question 5 of 65 > >> (a 31

Answer 1

Streptomycin.

Here for all four antibiotic, the zone of inhibition is 19mm . It is seen that for Streptomycin the zone of inhibition for Staphylococcus lies in the suseptible range (>14 mm), thus showing that streptomycin can act as a good antibiotic for this organism.

Antibiotic suseptibility test or Kirby Bauer method is used to test the efficacy of an antibiotic, aganist an organism. Here, a filter paper disc is loaded with a specific amount of antibiotic and placed on a lot of bacteria. The antibiotic will diffuses out of the disc and into the media , where it is taken by growing cell of bacteria. The bacteria which are suseptible to antibiotic will die off and the area with no bacterial growth surrounding the disc is called zone of inhibition. By looking at the size of this region, the researchers could infer if the strain is suseptible or resistant to certain antibiotic. As the zone of inhibition increases, the organism will be more suseptible to the antibiotic.